1. Field of the Invention
The present invention relates to the preservation of raw fruits, vegetables and their juices. More particularly, the present invention relates to the use of certain ascorbic acid esters, and compositions thereof, to control enzymatic browning in raw fruit and vegetable products.
2. Description of the Prior Art
Browning of raw fruits and vegetables due to mechanical injury, e.g., peeling, cutting, slicing, crushing etc., during postharvest processing has caused major losses in quality and value in the affected commodities. This enzymatic browning results from the polyphenol oxidase-catalyzed oxidation of phenolic compounds to O-quinones which sequentially polymerize to form dark-colored pigments.
Heretofore, efforts to control enzymatic browning in unblanched, cut fruits and vegetables have primarily involved sufite treatments to preserve their natural color. However, recent concerns over the adverse health effects from sulfites has stimulated much research to develop effective sulfite substitutes. A number of sulfite substitutes, mostly combinations of ascorbic or erythorbic acid with citric acid, phosphates and chlorides, have been developed. These formulations, however, do not usually provide the extended protection obtained with sulfites. This deficiency is due largely to the rapid oxidation of ascorbate or erythorbate, catalyzed by endogenous enzymes and copper in the raw commodity.
Consequently, there exists a need in the food industry for sulfite alternatives which are safe, economical and effective.